Determination of magneto-optical quality and refractive index of bismuth germanium oxide single crystals grown by Czochralski technique

Influence of femtosecond pulsed laser irradiation on bismuth germanium oxide single crystal properties

“…7. The results obtained for unirradiated crystals are in agreement with those given in [2,20]. Irradiation of the crystal caused all the peaks of symmetry type E, i.e., the peaks at 234, 454, and 619.6 cm À1 , to disappear and intensity increase of all other peaks.…”

“…As explained in detail in [20], the critical crystal diameter and critical rotation rate were calculated to be 12 mm and 20 rpm, respectively, whereas the pulling rate was determined experimentally to be 2.8-3 mm/h. The crystal puller MSR 2 combined with the Eurotherm temperature controller was used to grow the crystals.…”

“…Optical activity and Faraday rotation were measured at the wavelength of 632.8 nm by an orthogonal polarization detection polarimetric method described in detail in [20]. Output signal voltages U 1 and U 2 , obtained respectively from vertically and horizontally polarized component of the laser beam transmitted by the Bi 12 GeO 20 crystal sample, after transimpedance stages are…”

“…Due to its photoconductivity, photochromism, photorefractivity, piezoelectricity, as well as to electro-optic and magneto-optic effects it supports [7,8], Bi 12 GeO 20 is suitable for a broad range of applications and devices such as optical limiting, holography, spatial light modulation, optical phase conjugation, optical memories, fiber optic sensors, Pockels cells [8][9][10][11][12]. The properties of non-doped as well as doped Bi 12 GeO 20 were investigated and reported in a number of studies, for example in [13][14][15][16][17][18][19][20][21]. Characteristics of Bi 12 GeO 20 single crystals after exposure to thermal treatment [16][17][18][19]22], to beams of electrons [23], uranium ions [24], fluorine ions [15], g-ray [19] or light [9,18,22,[25][26][27][28] were investigated.…”

“…However, to the best of our knowledge, photo-induced increase in BGO transmission has not been reported so far. Therefore, following the determination of magneto-optical quality and refractive index of BGO single crystals presented in [20], we studied the influence of the femtosecond laser irradiation on Bi 12 GeO 20 single crystals. The irradiation caused permanent changes visible to the naked eye, as can be seen in Fig.…”